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EAchine E012
- goebish
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www.dropbox.com/sh/8dd1hvli0qt7fw4/AABlW...kQJymHNNEfjViga?dl=0
Power is now limited to 30mW for this protocol.
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- SeByDocKy
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- goebish
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Mine is working fine up to 30mW, but seems ymmv :/
edit: I'll take a look at the signal with the hackrf to try to understand what's happening, but I doubt I can do anything ...
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- goebish
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- goebish
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During bind, expected center frequency is 2460 MHz.
With the nrf24l01, there's a +33 kHz drift:
While with the hs6200 there's a -44 kHz drift (also, the signal is pretty dirty ):
Those drifts in opposite direction (77 kHz) could explain the problem, maybe a RF expert can confirm that ?
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- goebish
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The only way to fine-tune the drift on the nrf24l01 would be to replace the load capacitors that are around its crystal, but that's not a proper solution, except if the only model you want to control with the nrf24 is the E012
I'll also trim the antenna on the Rx, I noticed it's almost 40mm long ...
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- goebish
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- goebish
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- goebish
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www.dropbox.com/sh/8dd1hvli0qt7fw4/AABlW...kQJymHNNEfjViga?dl=0
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- SeByDocKy
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- goebish
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I consider it's not good enough to be pushed into main branch for now.
The CYRF6936 can do gfsk @ 1 Mbps, I've to check if it can be fine-tuned ...
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- goebish
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In GFSK mode, data is transmitted at 1 Mbps, without any DSSS: cool, that's exactly what we need, no DSSS and no Pseudo Noise !
Registers 0x1b & 0x1c: TX_OFFSET
Synthesizer offset value. This is a 12 bit 2’s complement signed number, which may be used to offset the transmit frequency of the device by up to ±1.5 MHz. A positive value increases the transmit frequency, and a negative value reduces the transmit frequency. A value of +1 increases the transmit frequency by 732.6 Hz; a value of –1 decreases the transmit frequency by 732.6 Hz
I've never worked with the cyrf6936 yet, that's a good opportunity, but it might take some time
If only the nrf24l01 had this feature as well ...
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- goebish
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cyrf in gfsk mode, SOP & CRC disabled, transmitting 0x55aa preamble (customable) + 00 ff 00 ff 00 ... 16 byte payload
... now I've to be able to send a payload longer than 16 bytes (27 bytes are needed in total for the E012 protocol, including HS6200 preamble), with the cyrf that's possible to send a payload up to 255 bytes (or 40, that's not clear ...) but it has to be done in 16 byte bursts, the fifo has to be refilled while the radio is transmitting ... Fortunately interrupts are triggered to find out when half or all bytes-1 of the fifo have been sent. I've to experiment and get the timing right.
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- goebish
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I'm somewhat able to receive packets sent by the cyrf with a nrf24l01, but they're corrupt and I think I understand why, nrf24l01 (and hs6200) has ±160 kHz gfsk deviation while the cyrf has ~±300 kHz... and it's not customable.
So, in the end I can't do anything better than with the nrf24l01, they're the 2 only radio we're supporting that can do gfsk @ 1 Mbps.
Oh well, at least I've learned how to use the cyrf, I did not waste my time ...
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- goebish
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- it kinda works with the nrf24l01
- no way to make it work with the cyrf6936
- now let's try with gnuradio / HackRF
Seems to work but there's a 1 second latency, probably because hackrf/osmocom buffer is too large. I think I've found someone that should be able to help me with that...
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- Fernandez
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- goebish
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This is known issue with the hackrf (no customable USB buffer size), but it should be fixed eventually.
Still, I'm not really sure of what the problem is with hs6200/nrf24l01 as they both can work with quite a bit of frequency drift, I've checked with SDR ...
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